Longitudinal changes of choroid plexus volumes and MRI ratios in multiple sclerosis

This longitudinal study aimed to identify the predictive role of choroid plexus enlargement for disability progression and its association with tissue damage in early multiple sclerosis patients. Forty patients with clinically isolated syndrome or early relapsing-remitting multiple sclerosis underwent brain MRI scanning at baseline, after 2 and after 6-8 years. FreeSurfer segmentation was used for brain volume estimation, and the choroid plexus was segmented by use of an independent automated segmentation tool. MRI ratios (T1 weighted through fluid attenuated inversion recovery image values) were calculated after calibration and subtracting lesion masks. Lesion masks were eroded to obtain both lesion rims and centres, for which mean ratios were extracted in addition to normal-appearing white matter. Expanded Disability Status Scale and disease duration were collected from neurological examination. Between baseline and last follow-up, choroid plexus volumes increased, and MRI ratios in lesions decreased significantly, which was dominated by the decrease in clinically isolated syndrome rather than relapsing-remitting patients and more pronounced in lesion rims than in their centre. Choroid plexus volumes were significantly related to MRI ratios within rims of lesions at baseline and within lesion centres after 6-8 years, but not within normal-appearing white matter. No associations between choroid plexus volumes or ratios and disability were found. We observed longitudinal changes of both choroid plexus enlargement and MRI ratios over 6-8 years in early multiple sclerosis patients. Choroid plexus enlargement seemed involved in the dynamic development of lesion destructivity.